Service Procedure

A. Inspect Harness and Harness Connector for Corrosion

1. Open the hood.

2. Disconnect both negative battery cables.





3. Disconnect the three (3) harness connectors from the PCM (Figure 1).

4. Inspect the connectors and PCM for the presence of corrosion.

> If no corrosion is found in the PCM connector and/or on the PCM pins continue with Section "B, Install Harness Connector O-rings."

> If corrosion is found in the PCM harness connector and/or on the PCM pins continue with Section "C, Replace the PCM and Transmission Wiring Harness."

B. Install Harness Connector O-Rin2s

1. Using a dry shop towel, clean off any dirt or moisture from the connector.





2. In stall one of the supplied 0-rings onto each of the three PCM harness connectors as shown in Figure 2.

3. Carefully connect the black (lowest) wiring harness connector to the PCM.

CAUTION:
When connecting the harness connector to the PCM, push against the lock tabs. The connector is fully seated when two clicks are heard. Verify that the connector is fully engaged by attempting to gently pull the connector from the PCM.

4. Repeat Step 3 of this procedure for the white (center) connector and then the gray (top) connector.

5. Connect both negative battery cables. Tighten the battery cable terminal clamp pinch bolts to 35 in. lbs. (4 N.m).

6. Close the hood and return the vehicle to the customer.

C. Replace PCM and Transmission Wiring Harness

NOTE:
Only those vehicles that have corrosion found during the inspection in Section A. require PCM and wiring harness replacement. Very few vehicles are expected to require PCM and wiring harness replacement.

IMPORTANT:
Due to a revised seal design on the PCM, the PCM connectors on the new wiring harness do not require the installation of 0-Rings.





1. Disconnect the 14-way wiring connector at the wiper cowl (Figure 3).

2. Disconnect the vacuum pump harness connector (Figure 3).

3. Disconnect wiring harness ground eyelet at the right fender (Figure 3).

4. Remove the wiring harness and harness cover from the wiper cowl.





5. Disconnect the bulk head connector (Figure 4).

6. Raise the vehicle on an appropriate hoist.





7. Disconnect the two 14-way connectors located next to the transmission bell housing (Figure 5).

8. Disconnect the PRNDL switch connector (Figure 5).

9. Disconnect the transmission solenoid connector (Figure 5).

10. Disconnect the output speed sensor connector (Figure 5).

11. For trucks equipped with electric shift transfer case, disconnect the electric transfer case motor and encoder connectors (Figure 5).

12. Disconnect the wiring harness routing clips.

Important:
Note the wiring harness routing before removing the harness from the vehicle.

13. Lower the vehicle.

14. Remove the transmission wiring harness from the vehicle.





15. Remove the PCM mounting screws and remove the PCM (Figure 6).

16. Install the new PCM into position. Tighten the mounting screws to 35 in. lbs. (4 N.m) (Figure 6).

17. Place the new harness into position.

18. Raise the vehicle on the hoist.

19. Install the wiring harness routing clips.

20. For trucks equipped with electric shift transfer case, connect the electric transfer case motor and encoder connectors (Figure 5).

21. Connect the output speed sensor connector (Figure 5).

22. Connect the transmission solenoid connector (Figure 5).

23. Connect the PRNDL switch connector (Figure 5).

24. Connect the two 14-way connectors located next to the transmission bell housing (Figure 5)

25. Lower the vehicle.

26. Connect the bulk head connector (Figure 4).

27. Install the wiring harness and plastic harness cover onto the wiper cowl.

28. Connect wiring harness ground eyelet at the fender (Figure 3).

29. Connect the vacuum pump harness connector (Figure 3).

30. Connect the 14-way connector near the wiper cowl (Figure 3).

31. Carefully connect the black (lowest) wiring harness connector to the PCM.

CAUTION:
When connecting the harness connector to the PCM, push against the lock tabs. The connector is fully seated when two clicks are heard. Verify that the connector is fully engaged by attempting to gently pull the connector from the PCM.

NOTE:
Due to a revised seal design on the PCM, the new wiring harness PCM connectors do not require the installation of 0-Rings.

32. Repeat Step 31 of this procedure on the white (center) PCM connector and then the gray (top) PCM connector.

33. Connect both negative battery cables. Tighten the battery cable terminal clamp pinch bolts to 35 in. lbs. (4 N.m).